Zero temperature black holes in semiclassical gravity

The semiclassical Einstein equations are solved to first order in $\epsilon = \hbar/M^2$ for the case of an extreme or nearly extreme Reissner-Nordstr\"{o}m black hole perturbed by the vacuum stress-energy of quantized free fields. It is shown that, for realistic fields of spin 0, 1/2, or 1, any zero temperature black hole solution to the equations must have an event horizon at $r_h < |Q|$, with $Q$ the charge of the black hole. It is further shown that no black hole solutions with $r_h < |Q|$ can be obtained by solving the semiclassical Einstein equations perturbatively.Comment: 7 pages, to appear in the Proceedings of the Ninth Marcel Grossmann Meeting, change in titl

Designing Philosophers

From the classical conceptualisations and discourses of Aristotle and Plato to the disturbing situatedness of the existentialists, philosophy provides perspectives on aspects of existence, thought and knowledge that illuminate and explain as well as connecting the somewhat specialised and inaccessible theory of software and systems engineering to the wider consciousness. This paper summarises the positions of selected philosophers that have been interpreted by some influential authors in software engineering to strengthen their arguments and in turn influence software methodology. Consideration of these philosophical perspectives can usefully influence the design of research projects and the analysis of results, particularly where the enquiry involves the business, industrial and other situated contexts in which contemporary system design and development is done

Patterns as Software Design Canon

This paper explores the value of the architecture profession’s notion of ‘the canon’ as a design transfer and knowledge transmission model for software architecture, and the overlap with the design patterns movement. The emerging body of architectural and design patterns has already become a kind of software ‘canon’— patterns and pattern languages exemplify design and act as design archetypes, have shared visibility through conventional and online media, and result from an established and intensive canonisation process consisting of shepherding (mentored authoring) and writer’s workshops (a review protocol). Research is underway to understand the need for a ‘software design canon’ and its accompanying discourse, and how well the design pattern form can fulfil this need

Personalized medicine : the impact on chemistry

An effective strategy for personalized medicine requires a major conceptual change in the development and application of therapeutics. In this article, we argue that further advances in this field should be made with reference to another conceptual shift, that of network pharmacology. We examine the intersection of personalized medicine and network pharmacology to identify strategies for the development of personalized therapies that are fully informed by network pharmacology concepts. This provides a framework for discussion of the impact personalized medicine will have on chemistry in terms of drug discovery, formulation and delivery, the adaptations and changes in ideology required and the contribution chemistry is already making. New ways of conceptualizing chemistry’s relationship with medicine will lead to new approaches to drug discovery and hold promise of delivering safer and more effective therapies

Reconciling transport models across scales: the role of volume exclusion

Diffusive transport is a universal phenomenon, throughout both biological and physical sciences, and models of diffusion are routinely used to interrogate diffusion-driven processes. However, most models neglect to take into account the role of volume exclusion, which can significantly alter diffusive transport, particularly within biological systems where the diffusing particles might occupy a significant fraction of the available space. In this work we use a random walk approach to provide a means to reconcile models that incorporate crowding effects on different spatial scales. Our work demonstrates that coarse-grained models incorporating simplified descriptions of excluded volume can be used in many circumstances, but that care must be taken in pushing the coarse-graining process too far

Gauge Invariant Effective Stress-Energy Tensors for Gravitational Waves

It is shown that if a generalized definition of gauge invariance is used, gauge invariant effective stress-energy tensors for gravitational waves and other gravitational perturbations can be defined in a much larger variety of circumstances than has previously been possible. In particular it is no longer necessary to average the stress-energy tensor over a region of spacetime which is larger in scale than the wavelengths of the waves and it is no longer necessary to restrict attention to high frequency gravitational waves.Comment: 11 pages, RevTe

Video-rate 3D Particle Tracking with Extended Depth-of-field in Thick Biological Samples

We present a single-aperture 3D particle localisation and tracking technique with a vastly increased depth-of-field without compromising optical resolution and throughput. Flow measurements in a FEP capillary and a zebrafish blood vessel are demonstrated experimentally